So. Calif. — Adding insulation to existing walls that have fiberglass batts
Kay Park| Posted inGeneral Questionson
I have a solidly built building – wood frame stucco walls. Built in 1960, (I helped) with rolls of pink fiberglass in the walls and attic. It is no longer effective against the heat.
What can we do to add wall insulation. I have had the walls of other homes insulated with blown in cellulose with success, but there was no existing insulation in those situations. Will blown in work with the old fiberglass in the wall cavity?
Is there a better option?
Thank you.
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Replies
I have read about people mentioning Air-krete in the past. I'm not certain about their success. It may be worth a call to the company. I have also heard about slow-rise cavity fill urethane foams. In my opinion I question the chemistry and health affects associated with these chemicals, installer training and the manufacturing process within your homes walls.
http://airkrete.com/gallery.php
http://www.airkrete.com/testResults_files/HPMA-NoFormaldehyde.pdf
Kay,
I have heard of some cellulose contractors blowing celluose into stud bays that already include fiberglass batts, but I don't recommend the practice. You'd have to drill a lot of access holes, and it's doubtful that the improvement in thermal performance would be worth the hassle.
If your house is overheating, the usual first steps include:
1. Trying to shade the windows on the exterior (for example, with awnings);
2. In some cases, replacing the existing windows with new windows that have low-SHGC glazing;
3. Sealing air leaks in your home's thermal envelope;
4. Adding attic insulation.
Of course, it's always possible to beef up your wall insulation -- for example, by installing a layer of rigid foam on the exterior side of your walls, followed by new siding -- but it's highly unlikely that this type of expensive retrofit work would be cost-effective.